The present invention relates to a flightless rock auger suspended from a derrick and powered by a shaft linked to a power source for removing plugs of rocks from post holes.
Poles for power lines and communication purposes are required to be vertical and arrange din straight lines. The poles may be planted in positions which are relatively inaccessible. A crane may be utilized for providing an outreaching means. Typically a digger derrick consists of a telescopic mobile crane from which is suspended a torque head. A flighted auger is suspended from the torque head and utilized for drilling in soil containing loose rock. The digger derrick is advantageous for extending the auger to the desired location. The auger may be stowed in a fixed position or extended in a telescoping position as needed to reach the desired location for drilling the hole.
Depending on the nature of the digging device, its digging element, or auger, torque head or hydraulic pressure is typically exerted on the digging element via air or oil hydraulic pressure exerted by the crane or cylinder in cooperative engagement therewith for forcing the digging element into the earth.
Although the conventional flighted auger is adequate for drilling through soil, or even soil with loose rock, the drilling operation must be suspended upon hitting a large rock or rock ledge because the flighted auger cannot penetrate the hard rock surface. The flighted auger is then lifted out of the hole and conventional methods of removing the obstruction with a steel shaft, crowbar, or explosive charge are used to break-up the hard rock. The flighted auger is then lowered back into the hole to remove the loose rock.
A considerable amount of time is lost during the rock break-up and removal procedure. Moreover, an effort is continually being made to minimize work with explosives due to the liability of injury to workers and/or damage to residents or businesses in the area which may be in the area of the blasting zone and susceptible to rock or vibration damage.
The present invention achieves the above objects by providing a flightless rock auger for drilling postholes through rock and hardpan.
The flightless rock auger is used for drilling postholes through rock without the use of hydraulic pressure and at slow revolution per minute. The rock auger is used in combination with a conventional flighted auger used for drilling postholes in dirt and clay. During a posthole drilling operation, the rock auger is substituted for a conventional flighted auger as needed for drilling through and removing rock or other hard material such as concrete from the posthole. The rock auger is designed for use at very low revolutions per minute and can function utilizing only the weight of the auger and shaft and does not require any additional hydraulic pressure for cutting a circular hole through the rock and forming a plug which is to be lodged in the cavity of the rock auger cylinder to be removed from the posthole. The quick connection shaft enables the conventional flighted auger to be quickly substituted for the rock auger to facilitate fast removal of soft dirt from the posthole. Moreover, one or more slots can be formed in the coupling connecting the auger shaft to the drive shaft of the power unit in providing a limited amount of play or movement enabling the rock auger to float if desired and reduce shock and vibration to the drive unit. A center drill bit can be disposed within the cutting head for extending outwardly pass the cutting edge thereof for starting the hole, breaking up rock, and holding the auger in position during the drilling operation. A portion of the cutting head extending from the cutting edge upward a selected distance to as far as the upper edge of the cutting head may be removed providing access and quick removal of the plug formed therein.
The present invention provides a flightless rock auger having a cylindrical hollow cutting head and a plurality of teeth extending from the lower periphery thereof. A support member extends across a portion of the cylindrical hollow cutting head providing a means for cooperative engagement with a shaft extending outwardly therefrom. A quick disconnect coupling is disposed upon the distal end of the shaft.
A preferred embodiment of the flightless rock auger system for use with a drilling rig includes a flightless rock auger having a cylindrical hollow cutting head with a plurality of cutting teeth extending from the bottom edge of the cutting head. A support member extends across a portion of the cylindrical hollow cutting head providing a means for cooperative engagement with a vertical drive shaft extending outwardly therefrom. A quick disconnect coupling is disposed upon the distal end of the shaft. A means for rotating the drive shaft such as a mechanical or fluid drive may also power the hydraulic mechanism for lifting and lowering the drive shaft which utilizes its own weight for exertion of downward pressure onto the hard substrate. Of course, it is contemplated that the weight of the boom or hydraulic pressure may be provided if available to increase the rate of drilling without damaging the rock auger.
A method of removing hard substrate from a posthole, using a flightless rock auger with a drilling rig simply requires the attaching a flightless rock auger having a cylindrical hollow cutting head and a plurality of cutting teeth extending from the bottom edge of the cutting head. A support member extends across a portion of the cylindrical hollow cutting head providing a means for cooperative engagement with a vertical drive shaft extending outwardly therefrom. A quick disconnect coupling is disposed upon the distal end of the shaft to means for rotating the drive shaft. The flightless rock auger is lowered into a posthole containing a hard substrate and resting the flightless rock auger onto the hard substrate. The auger is rotated at a very low rpm typically less than 20 revolutions per minute (rpm) and preferably less than 10 rpm, usually from about 3 rpm to about 10 rpm forming a plug of hard substrate inside of the cylindrical body of the flightless rock auger. Lifting the flightless rock auger and the plug from the posthole is simple and the plug of the hard substrate is removed from the flightless rock auger head. The flighted auger is then substituted for removing soil from the posthole.
The flightless rock auger comprises a cylindrical head defining a plurality of teeth extending downwardly from the periphery of the bottom edge at a selected forward angle. The top of the head is connected to a shaft having a quick disconnect adapter on the opposing distal end.
The rock auger is utilized in combination with a conventional flighted auger used for drilling postholes in dirt and clay. During a posthole drilling operation, the rock auger is substituted for the flighted auger when needed to drill through and remove rock or other hard material such as concrete from the posthole. The rock auger is designed for use at very low revolutions per minute and utilizes only the weight of the auger and shaft and does not require any additional hydraulic pressure for cutting a circular hole through the rock and forming a plug which is be lodged in the cavity of the rock auger cylinder to be removed from the posthole. The quick connection shaft enables the conventional flighted auger to be quickly substituted for the flightless rock auger to facilitate fast removal of soft dirt from the posthole. The rock auger provides a means for utility companies to utilize a means for drilling postholes for electric poles, telephone poles, pilings, and the like without the use of explosives; thereby providing a safer means of excavation.
When the drilling operation encounters rock, rather than blasting through the rock with explosives, or calling a truck utilize a pressurized auger with flights, the non-pressurized flightless rock auger can be fitted onto the torque head of a conventional drilling shaft and used to drill through the rock. A plug may be formed in the head by the drilling operation; however, the plug is removed by using had tools which fit into openings formed in the top end of the drilling head.
A preferred embodiment of the present invention defines a flightless rock auger for removing plugs of hard material from post holes. The rock auger includes a cylindrical hollow cutting head having a hollow cylindrical body defining side walls connecting a top end defining an upper peripheral edge and a lower open end defining a lower peripheral cutting edge including a plurality of teeth extending from the lower peripheral edge. The top end of the hollow cylindrical body includes at least one support member extending across at least a portion of the top end joining the side walls. A shaft having a diameter less than the cutting head includes a proximal end connecting to the at least one support member and having an opposing distal end extending therefrom. A quick disconnect coupling disposed upon the opposing distal end of the shaft includes means for a floating attachment to a drive shaft of a power unit providing limited vertical movement therebetween.
Moreover, the power drive shaft of the auger drive unit can also be connected to the shaft of the auger by a coupling which limits or even eliminates any xe2x80x9cplayxe2x80x9d and provide a tight cooperative engagement therebetween. The auger and cutting head will still xe2x80x9cfloatxe2x80x9d in that only the weight of the auger will be necessary to cut through the rock substrate. If desired the cutting may be faster by also letting the power drive boom weight rest on the auger thereby floating on the rock substrate during the drilling process. Of course, applying downward pressure to the auger by use of the boom is an option; however, unnecessary to obtain good performance.
Accordingly, it is a principal object of the present invention to provide a flightless auger device for digging through hard rock.
It is another object of the present invention to provide an flightless auger which is capable of drilling through rock and forming a plug removable from the flightless auger.
It is another object of the present invention to provide a flightless auger utilizing an attachment means which is interchangeable with the attachment means typically used with conventional flighted augers for drilling operations.
It is therefore another object of the present invention to design a flightless auger for use at very low revolutions per minute (rpm) to maximize safely and prevent damage to the equipment.
It is an object of the present invention to provide an adapter extending from a shaft for use with a torque head of a drilling derrick.
Another object is to provide a flightless auger having teeth extending outward at a forward angle.
It is another object to provide a flightless auger having a drill head portion utilizing an end diameter of greater diameter than the plug receiving inner diameter.
It is yet another object of the present invention to utilize a plurality of diagonal ribs to minimize suction between the exterior of the drilling head and the walls of the drilled hole.
It is yet another object of the present invention to provide an access port in the top end of the drilling head for removal of the rock plug formed therein.
The rock auger provides an alternative method for utility companies to drill postholes for electric poles, telephone poles, pilings, and the like without the use of explosives thereby providing for safer excavation.